Ricin poisoning: a comprehensive review.

Context: The recent discoveries of ricin, a deadly biologic toxin, at a South Carolina postal facility, a White House mail facility, and a US senator's office has raised concerns among public health officials, physicians, and citizens. Ricin is one of the most potent and lethal substances known, particularly when inhaled. The ease with which the native plant (Ricinus communis) can be obtained and the toxin extracted makes ricin an attractive weapon.

Objectives: To summarize the literature on ricin poisoning and provide recommendations based on our best professional judgment for clinicians and public health officials that are faced with deliberate release of ricin into the environment. LITERATURE ACQUISITION: Using PubMed, we searched MEDLINE and OLDMEDLINE databases (January 1950-August 2005). The Chemical and Biological Information Analysis Center database was searched for historical and military literature related to ricin toxicity. Book chapters, unpublished reports, monographs, relevant news reports, and Web material were also reviewed to find nonindexed articles.

Results: Most literature on ricin poisoning involves castor bean ingestion and experimental animal research. Aerosol release of ricin into the environment or adulteration of food and beverages are pathways to exposure likely to be exploited. Symptoms after ingestion (onset within 12 hours) are nonspecific and may include nausea, vomiting, diarrhea, and abdominal pain and may progress to hypotension, liver failure, renal dysfunction, and death due to multiorgan failure or cardiovascular collapse. Inhalation (onset of symptoms is likely within 8 hours) of ricin is expected to produce cough, dyspnea, arthralgias, and fever and may progress to respiratory distress and death, with few other organ system manifestations. Biological analytic methods for detecting ricin exposure are undergoing investigation and may soon be available through reference laboratories. Testing of environmental samples is available through federal reference laboratories. Currently, no antidote, vaccine, or other specific effective therapy is available for ricin poisoning or prevention. Prompt treatment with supportive care is necessary to limit morbidity and mortality.

Conclusion: Health care workers and public health officials should consider ricin poisoning in patients with gastrointestinal or respiratory tract illness in the setting a credible threat. Poison control centers and public health authorities should be notified of any known illness associated with ricin exposure.